Transfer finger assembly



July 7, 1964 G. s. WILLIAMS 3,140,113

TRANSFER FINGER ASSEMBLY Filed Feb. 8, 1962 n* Y r i.; i; 29 g2g.

/9 y l i INVENTOR @bf2/7 6.' #J7/fama ATTORNEY United States Patent O 3,146,113 TRANSFER FINGER ASSEMBLY Glenn S. Williams, Myerstown, Pa., assignor to Bethlehem Steel Company, a corporation of Pennsylvania Filed Feb. 8, 1962, Ser. No. 171,998 Claims. (Cl. 294-86) This invention relates in general to a transfer mechanism and more particularly to a transfer finger assembly which includes resilient means for facilitating the gripping of a blank or article to be transferred.

In -a machine `where la blank is automatically positioned at a plurality of stations, an important part in the efficient operation of the machine is the transfer mechanism. A significant component of the transfer mechanism is the arrangement of members adjacent the blank to be transferred. These members are usually called transfer finger assemblies. In one type of transfer mechanism and at the appropriate time in the machine cycle, two transfer finger assemblies move towards each other and come to rest at a first station in such a position that the effective distance between the assemblies is less than the size of the blank to be transferred. After the transfer finger assemblies are so positioned, a blank is forced between them. Since the blank is greater in size than the effective distance between the assemblies, springs are usually arranged on one or both transfer finger assemblies or in other parts of the transfer mechanism to .absorb this difference in size and provide the proper gripping force. After so -gripping 4the blank, the transfer mechanism causes the transfer finger assemblies holding the blank to be indexed to a secend station, and the blank is forced out of the transfer finger assemblies, whereupon the assemblies move away from each other and are returned to the first station and the cycle is repeated. It is `of utmost importance for the reliable and efficient operation of the transfer mechanism that the transfer finger assemblies transmit the proper force to the blank and be sufficiently strong to sustain the repeated operation. Also, the-arrangement should be capable of automatically adjusting to differences in size and/ or position of the article to be transferred and be arranged so that possible scale from the blank or other foreign matter will not adversely affect the operation. The assemblies must also be capable of automatically releasing the blank if vfor some reason the blank is acted upon by a force substantially normal to the effective gripping force. j

This invention provides such a transfer yfinger assembly comprising a freely supported leaf spring'. A lfirst element of the leaf spring isconnectedsto a base member attached to the actuating mechanism and a secondelement in spaced relation to the first element supports a gripperv block in contact with the article to be transferred. This arrangement .allows movementin a plurality of directions while exerting the proper gripping force. In addition to the above, the transfer finger assembly is relatively simple, reliable and economical.

One of the objects of this invention is to provide a transfer finger assembly which can adjust automatically to differences in the size and/or position of the article or blank to be transferred.

Another object of this invention is to provide -a transfer finger assembly which is relatively simple and economical while possessing the desired strength and reliability of operation.

Still other and further objects of this invention will appear inthe specification and claims.

In the drawings:

FIG. 1 is a front view of the transfer finger assemblies just prior to the entry of a nut blank.

FIG. 2 is a front view similar to FIG. l, after the nut 3,149,113 Patented .luly 7, 1964 blank has been forced between the transfer yfinger assemblies and is being gripped.

FIG. 3 is a sectional view of FIG. 1 along the line 3-3.

FIG. 4 is a front view similar to the lower part of FIGS. l `and 2, but on a larger scale and showing another form of leaf spring.

With particular reference to FIGS. l, 2 and 3, reference numeral 10 indicates generally a first transfer finger assembly attached by integral rod 11 to an actuating mechanism (not shown) for movement in the general directions indicated by arrows 12 and 13. As shown, -transfer finger assembly 10 is provided with integral projecting members 14, 14 having appropriate article contact surfaces 15, 15. A second transfer finger assembly generally designated as 16 is positioned opposite transfer finger assembly 10 and is attached to an actuating mechanism (not shown) for movement in the general directions indi# cated by arrows 17 and 1S. The second transfer finger assembly 16 includes a base member 19 having integral key 29 and slotted openings 21 for admitting bolts (not shown) for attachment to the actuating mechanism (not shown). Freely supported by thevbase member 19 is a substantially oval leaf spring generally indicated as 24. As best shown in FIGS. l and 2, leaf spring 24 comprises two half sections 25 and 26. It is apparent that in place of the two half sections one continuous substantially oval leaf spring could be utilized. Bolts 22, 22 pass through openings in the lower side of leaf spring sections 25 andV 26 and are in threaded engagement with openings in the base member 19. Bolts 22, 22 project into the slotted openings 21, 21 and are in contact with the bolts (not shown) which connect the base member 19 to the actuating mechanism (not shown). Nuts 23, 23 in threaded engagement with bolts 22, 22 secure the leaf spring sections 25 and 26 to base member 19 and also lock the bolts 22, 22 Vin position. It can be seen that by varying the amount the bolts 22, 22 project into slotted openings 21, 21 the position of the transfer finger assembly can be varied -with respect tov the actuating mechanism (not shown). Supported by the leaf spring 24 on the side opposite the base member 19 is a gripper block 27 having appropriate contact surfaces 31 and 32. Bolts 28, 28 releasably attach the gripper block 27 'to upper side of half sections 25, 26 of leaf spring 24. Positioned between the leaf spring 24 and the base member 19 is a spacer 29. A similar spacer 30 is positioned between the gripper block 27 and the leaf spring 24. These spacers 29 and 30 provide 4one means for adjusting the position of the gripper block 27 in response to extreme variations in the size of the hex nut blank. In addition, the position of the transfer `finger assembly 16 and thus gripper block 27 may be adjusted by means of bolts 22, 22 as described above.

FIG. 4 discloses a transfer finger assembly 16 utiliz# ing a substantially U-shaped leaf spring 33. It should be understood that `a transfer finger assembly similar to that shown in FIGS. l, 2 and 3 and generally designated as 10 would be used in conjunction with the transfer iinger assembly shown in conjunction with the transfer finger assembly shown in FIG. 4. U-shaped leaf spring 33 is supported on base member 19 and has one leg connected thereto by means of bolts 22, 22 and nuts 23, 23. Base member 19 is identical with the base member described above for FIGS. l, 2 and 3 and bolts 22, 22 and nuts 23, 23 function as described above. Connected to the other leg of U-shaped leaf spring 33 by means of bolts 2S, 28 is a gripper block 27. Gripper block 27 and spacers 29 and 30 are also identical with like parts in FIGS. l, 2 and 3. Bolts 28, 23 pass through a slotted opening in leaf spring 33 and are in threaded engagement with an opening in gripper block 27. Bolt 34 is in threaded engagement with an opening extending into the end of the U-shaped leaf spring adjacent the gripper block 27 and is in contact with one of the bolts 2S. This arrangement allows the gripper block 27 to be positioned along leaf spring 33. Nut 35 in threaded engagement with bolt 34 is used to lock bolt 34 in a given position.

While the description and drawings disclose an arrangement for gripping a nut blank 40 (FIG. 2), it is apparent that the gripping of other articles or blanks of a different cross section can be provided for by changing the shape of the article contact surfaces on one or both transfer finger assemblies.

In operation and prior to gripping the nut blank 40 the opposed transfer finger assemblies and 16 are located a substantial distance apart. At the appropriate time, the actuating mechanism (not shown) causes the first transfer finger assembly 10 to move in the direction generally indicated by arrow 12 and the second transfer finger assembly 16 to move in the direction generally indicated by arrow 17. The two transfer finger assemblies 10 and 16 proceed towards each other until integral members 14, 14 having contact surfaces 15, 15 and surfaces 31, 32 of gripper block 27 are spaced at a distance less than the comparable size of the nut blank 40. The nut blank 40 is then forced between the two transfer finger assemblies by a punch or pusher rod (not shown). To facilitate the entry of the nut blank 40 a tapered surface 36, 36 is provided on projecting members 14, 14 of transfer finger assembly 10 and a similar tapered surface 37, 38 is provided on gripper block 27. After the nut blank 40 has been forced between the transfer finger assemblies 10 and 16 and is in contact with surfaces 15, 15 of projecting members 14, 14 and surfaces 31, 32 of gripper block 27, the actuating mechanism (not shown) causes the transfer nger assemblies to be indexed to another station. At this station the nut blank 40 is then forced out of the transfer finger assemblies 10 and 16 by a punch or pusher rod (not shown). Thereafter the assemblies 10 and 16 move in the general direction as indicated by arrows 13 and 18 respectively and return to the original station and the cycle is repeated.

It is evident that while the above description discloses movement of the transfer finger assemblies between stations it is possible to provide for opening and closing of the transfer fingers while the station is moved relative thereto. Also it is evident that instead of forcing the blank between the closed transfer finger assemblies, the assemblies could be arranged to close upon a properly positioned blank.

In addition to providing the required gripping force, the above arrangements allow the transfer finger assemblies 10 and 16 to release the nut blank 40 if a force having a component of sufficient magnitude and in a direction substantially perpendicular to the effective gripping force is exerted on the blank. This provision aids in reducing damage to the transfer finger assemblies 10 and 16. If such a component of force is exerted on the blank 40 in the directions indicated by the arrow 39 (FIG. 2), the leaf spring would be further compressed and the nut blank 40 would slide out of contact with the transfer finger assemblies 10 and 16,

Since the leaf spring comprises a first element connected to the base member and a second element in spaced relation to the rst element supporting a gripper block 27, it can be seen that the gripper block 27 is free to move in a plurality of directions. For example, the gripper block 27 can move in the directions indicated by the arrow 39 (FIG. 2) or a direction perpendicular thereto or a combination of these directions. This flexibility of movement allows the gripper block 27 to adjust to different sizes and/or position of the blank. ln addition some misalignrnent between the two opposed transfer finger assemblies may be present without adversely affecting the proper gripping of the article to be transferred.

Although I have described my invention hereinabove in considerable detail, I do not wish to be limited narrowly to the exact and specific particulars disclosed, but I may also use such substitutes, modifications or equivalents as are included within the scope and spirit of the invention or pointed out in the appended claims.

I claim:

l. In a transfer mechanism including a pair of opposed transfer finger assemblies to contact an article to be transferred, a transfer finger assembly comprising a base member, a gripper block out of contact with said base member and in spaced relation thereto and a spring forming the sole means of securing said gripper block to said base member, said spring comprising a pair of spaced substantially parallel arm portions secured respectively to said gripper block and to said base member and an intermediate portion of generally U-shaped configuration connecting said arm portions.

2. A transfer finger assembly as defined in claim 1 including adjustable means to vary the position of said gripper block.

3. In a transfer mechanism including a pair of opposed transfer finger assemblies to contact an article to be transferred, a transfer finger assembly comprising a base member, a gripper block out of contact with said base member and in spaced relation thereto and a substantially oval leaf spring forming the sole means of securing said gripper block to said base member, said leaf spring having one side connected to said base member and the opposite side connected to said gripper block.

4. A transfer nger assembly as defined in claim 3 wherein said substantially oval leaf spring comprises two half sections.

5. A transfer finger assembly as defined in claim 3, including adjustable means to vary the position of said gripper block.

References Cited in the file of this patent UNITED STATES PATENTS 1,173,850 Oliver Feb. 29, 1916 2,323,654 Gordy July 6, 1943 2,448,402 Thompson Aug. 31, 1948 2,716,011 Steinmen Aug. 23, 1955 2,956,700 Quayle Oct. 18, 1960 

1. IN A TRANSFER MECHANISM INCLUDING A PAIR OF OPPOSED TRANSFER FINGER ASSEMBLIES TO CONTACT AN ARTICLE TO BE TRANSFERRED, A TRANSFER FINGER ASSEMBLY COMPRISING A BASE MEMBER, A GRIPPER BLOCK OUT OF CONTACT WITH SAID BASE MEMBER AND IN SPACED RELATION THERETO AND A SPRING FORMING THE SOLE MEANS OF SECURING SAID GRIPPER BLOCK TO SAID BASE MEMBER, SAID SPRING COMPRISING A PAIR OF SPACED SUBSTANTIALLY PARALLEL ARM PORTIONS SECURED RESPECTIVELY TO SAID GRIPPER BLOCK AND TO SAID BASE MEMBER AND AN INTERMEDIATE PORTION OF GENERALLY U-SHAPED CONFIGURATION CONNECTING SAID ARM PORTIONS. 